1. Field of the Invention
This invention relates to tube couplings.
2. Background Prior Art
UK-A-1520742 discloses a “Speedfit” connector comprising a coupling body with a throughway open at one end and a tapered cam surface in the open end to receive a collet for locking a tube in the coupling. The collet is compressed against the tube by a slight withdrawal of the tube/collet from the coupling body which locks the tube in the coupling body. The collet can be depressed into the body to release the tube when required.
UK-A-2167147 discloses a “SuperSeal” connector which is a modification of the “Speedfit” connector and has a separate sleeve screwed into the open end of the coupling body in which the tapered cam is formed. By screwing the sleeve into the coupling body the gripping action of the collet on the tube is increased. Also the collet becomes locked up in the coupling body and cannot be depressed to release the tube. The tube is then permanently locked in the coupling body.
EP-A-0945662 discloses a tube coupling having both “Speedfit” and SuperSeal” modes of operation. More particularly the coupling comprises a coupling body having a throughway open at one end to receive an end portion of a tube and having an internal cam surface tapering towards the open end in which a collet is located for locking the tube in the coupling body by engagement with the tapered cam surface and having stop means to limit entry of the collet into the throughway. The coupling body has a main portion, the throughway of which receives the end of the tube and contains said stop means to limit insertion of the collet and an end cap in screw threaded engagement with the main body. The end cap provides said open end to the throughway and the tapered cam surface. Indexing means are provided between the end cap and the main body to define different positions of rotation of adjustment in the first of which the tube can be inserted in and by depressing the collet into the coupling body, released in the coupling body (i.e. “Speedfit” mode) and in the second of which the collet is engaged with the stop means to prevent the collet being depressed into the coupling body to release the tube (i.e. “SuperSeal” mode).
EP-A-1398559 discloses a tube coupling comprising a coupling body having a throughway open at one end to receive a tube, an end cap in screw-threaded engagement with the coupling body to move between initial and advanced positions along the coupling body and having an opening for the tube and an internal cam surface tapering towards the tube opening, a collet in the end cap engaging the cam surface to lock a tube in the cap with movement of the collet outwardly of the cap and to release the tube when depressed inwardly of the cap, and stop means in the coupling body to limit movement of the collet inwardly of the end cap, the initial position of the end cap on the coupling body allowing a tube to be inserted and locked in the end cap by the collet and to be released by depressing the collet inwardly of the cap and the advanced position of the end cap holding the collet adjacent the stop means in the coupling body to prevent release of the tube; wherein detent means are provided acting between the cap and coupling body to provide resistance to movement of the cap along the coupling body until the cap reaches said initial position on the coupling body and to allow said further movement of the cap to the advanced position.